Interior finishing of underground areas (boiler rooms, townhouse basements, masonry basements) requires careful consideration of construction details, to avoid future problems with water infiltration, fungal growth, and indoor air quality. This plan relies upon an interior perimeter drain and sump pump to eliminate infiltrating groundwater by drawing the level down to the perimeter drain, and minimizing moisture migration through living space walls by waterproofing from the exterior. The following details are required based upon use of the area: